1. Field of the Invention
The invention is based on a high-pressure fuel system for internal combustion engines of the type disclosed in the patent application DE 198 27 628 A1.
2. Description of the Prior Art
A high-pressure fuel system of this kind, which in this application takes the form of a fuel injection valve, has a valve holding body and a valve body, which are pressed against each other by means of a tensioning nut. A supply conduit passes through the contact surface of the two bodies, through which highly pressurized fuel travels to the injection openings of the fuel injection valve. In order to assure the tightness of the supply conduit at it""s passage through the contact surface of the two bodies, raised regions are embodied on the contact surfaces of the two bodies, in particular surrounding the passage of the supply conduit. With constant tightening moment on the tensioning nut, the surface pressure in this region is increased so that a better seal of the supply conduit is produced. In this connection, however, the known high-pressure fuel system has the disadvantage that the production of such raised regions is relatively complex and therefore cost-intensive. Moreover, the two bodies are made of a hard steel, which does not plastically deform when compressed by the tensioning nut, so that high demands must be placed on the surface quality of the raised regions in order to achieve a favorable seal.
The high-pressure fuel system according to the invention has the advantage over the prior art that a sealing film is disposed between the two high-pressure bodies, which encompasses the passage of the conduit through the contact surface and thus produces a seal in a simple and inexpensive way. The sealing film in this connection can be embodied so that in addition to the supply conduit, it also encompasses other passages of conduits and bores that are embodied in the high-pressure fuel system. The sealing film can be separately produced and, for example, stamped out of a corresponding plate so that it is simple and inexpensive to produce.
It is particularly advantageous to use the sealing film according to the invention in a fuel injection valve in which the sealing film is disposed between a valve holding body, which is embodied as a high-pressure body, and a valve body, which is likewise embodied as a high-pressure body. Particularly in injection systems that operate with a constantly prevailing pressure in the valve body, so-called common rail systems, a favorable tightness of the supply conduit, which extends in the valve holding body, through the sealing surface, to the valve body, can be achieved through simple means.
In advantageous embodiment of the subject of the invention, the sealing film is comprised of a metal. This metal is preferably soft in comparison to the steel of which the two high-pressure bodies are made. It has turned out to be particularly advantageous to use copper or soft iron as the material for the sealing film.
The sealing film preferably has a thickness in the range of a few xcexcm up to a few hundred xcexcm. As a result, the sealing action and the flow properties of the sealing film when the two high-pressure bodies are clamped against each other can be optimally matched to the desired tightness.